Apparently, storing Coke syrup in stainless steel containers keeps it better preserved than the methods preferred by other competitors.

McDonald’s official website confirms that the fast food giant follows strict guidelines set by Coca-Cola to ensure it tastes the same as when you buy it in a bottle.

A McDonald’s spokesperson said: “Despite the speculation, there is no secret formula to our recipe. We’re delighted to hear that our customers enjoy drinking our Coca-Cola.”

The fast food giant ensures its syrups and drink fountain is ice cold.

Insulated tubing is run from the back refrigeration unit all the way to the front and drive-through units.

Keeping this water chilled is necessary to maintain superior CO2 levels, which means that it can become more carbonated. Better soda water ultimately makes for a crisper fizzy drink.

McDonald’s claim on their website: “The water and Coca-Cola syrup are pre-chilled before entering our fountain dispensers with the ratio of syrup set up to allow for ice to melt. We also keep our fountain beverage system cold so your drink can always be at the peak of refreshing.”

The soda water is constantly recirculated through this tubing system so that it can remain between 33-38 degrees (just above freezing) at all times.

McDonald’s invests a fair amount of money to ensure that each of its restaurants has a high-end water filtration system.

It said: “In order to ensure our drinks are always meeting a gold standard, we have proper filtration methods in place.”

It’s not just the technical machines – something as simple as the size of the straw makes all the difference too.

McDonald’s revealed: “There’s also our straw – it’s slightly wider than a typical straw, so all that Coke taste can hit all your taste buds.”